1. Field of the Invention
This invention relates in general to continuous hot rolling mills of the type producing rods, bars and the like, and is concerned in particular with an improved shear for trimming the front and back ends from hot rolled rods being delivered from the finishing stands of high speed rod mills.
2. Description of the Prior Art
Conventionally, the front and back ends of hot rolled rods are trimmed by shears located along the rolling line in advance of the finishing stands, where the product is moving at slower speeds. Some trimming shears operate intermittently, whereas others operate continuously. Intermittently operable shears necessarily require complex control systems which precisely position the shear blades during each cut in response to rod end position signals generated by sensors located along the rolling line. From the standpoint of control complexity, continuously operating shears such as disc shears are far less demanding, but they commonly produce sharply oblique cuts with undesirable jagged ends.
In any event, none of the conventional disc shears has been deemed capable of operating safely and reliably at delivery speeds on the order of 90 m/sec. and higher. Thus, the front and back ends of finish rolled rods must be trimmed manually after the laying head, either while the product is being conveyed in overlapping ring form on the cooling conveyor, or after the cooled rings have been gathered into a coil at the reforming station. Manual trimming is labor intensive, often inconvenient, and potentially hazardous to operating personnel.